WHEELING, Ill. — A small cargo jet crashed into a forest preserve Tuesday shortly after being cleared to land at a suburban Chicago airport. Officials said that it appears the two people aboard were killed.

Glenview Fire Department Battalion Chief Jim Fancher said a preliminary investigation indicated that a pilot and co-pilot were aboard the jet that crashed into the DesPlaines River in unincorportaed Glenview as it was making its final approach at about 1:30 p.m. to Chicago Executive Airport in nearby Wheeling. He said emergency crews were on the scene, including divers.

The Federal Aviation Administration, on the scene of the crumpled wreckage, said it was unclear what caused the crash, noting that the jet had just been cleared for visual approach to the airport.

The Learjet Model 35 left Oakland County International Airport in Waterford, Mich., about 1 p.m. Tuesday, said J. David Vanderveen, who oversees the county's three airports. Oakland County International Airport is about 25 miles northwest of Detroit.

Vanderveen said the jet was empty of cargo, but was to pick up freight at the Wheeling airport, located about 15 miles northwest of Chicago.

"There was a pilot and a co-pilot," Vanderveen said. "Both were commercially rated, which means they were professional pilots. My understanding is they were clear to land and landed short, and crashed into the Des Plaines River."

The jet, according to the FAA, was registered to the Waterford-based Royal Air Freight. A woman who answered the phone at the company declined to comment on the crash.

Photos posted on the Web site of WBBM-AM in Chicago showed crumpled chunks of the jet along the bank of the Des Plaines River.